Children infected by the human immunodeficiency virus develop cardiac muscle disease of unknown etiology, and occult in origin. Non-invasive testing has been implemented to follow the course of HIV cardiac disease in children. One aim of this study is to assess the relative value of different noninvasive diagnostic methods in the early detection of HIV cardiac disease. A second aim is to develop, through serial testing, a descriptive natural history of HIV cardiomyopathy, beginning with its preclinical manifestations. The results will aid in the management and, possibly, the prevention of HIV cardiac disease in children.